Presently, most distilleries use a conventional distillation process that requires temperature heat inputs (approx. 250° Fahrenheit) and distillation temperatures from 190° Fahrenheit (F) to 205° F. The following discussions describe concerns raised by this approach.
Heat input sources: A quality fuel is needed to produce the required heat for vaporization of the water into steam. Generally the source of the heat is a fossil fuel burner. This produces carbon dioxide associated with global warming, and removes a resource fuel that is better used elsewhere. In addition, subjecting the beer to these higher temperatures during distillation causes the production of unwanted volatile organic materials that can have a detrimental effect on the quality of the consumable spirit. In traditional distilleries often the liquor is subjected to multiple distillations and increasingly smaller cuts to remove some of these unwanted materials. This is energy wasting and effects product efficiency.
Alternate heat sources: Over thirty percent (30%) of the heat produced in the United States is lost due to the low quality of the heat byproduct and the lack of technology to take advantage of this very large resource. In addition, heat output from solar thermal and geothermal waste water systems also falls in this range as does the heat recovered from cogeneration systems. There is plenty of low grade waste heat and potential solar or geothermal generated heat in the 120° F.-155° F. ranges.
Oxygen exposure: Oxygen reacts with alcohol and other volatile organics including desired flavor producing compounds to produce an off taste distillate. In addition compounds can be produced that are toxic and produce hangover symptoms. These reactions are enhanced at the higher temperatures used in traditional distilleries. Minimizing the amount of oxygen in the distillation environment is therefore desirable for the production of a higher quality distillate.
High temperature effects on distilled spirit quality: High temperatures in the temperature range (190° F.-225° F.) used in traditional distilleries has a detrimental effect on distillers beer quality. At the higher temperatures there is a greater chance of cross reactions occurring in the beer especially if oxygen is not minimized. Also, there are yeast and yeast-by-products that are present in the beer that are heat sensitive. Yeast cells can be destroyed in the (190° F.-225° F.) temperate range, releasing chemicals into the beer. Some of these materials produced in the beer at high temperatures can be distilled and can produce off flavor spirit product and hangover symptoms. It is therefore desirable to distill at lower temperatures where these high temperature induced changes are minimized.